Effects of Growing Media on the Growth of Potted Hydrangea (Hydrangea macrophylla)

Abstract

This study aimed to investigate the effects of different growing media on the growth of potted hydrangea (Hydrangea macrophylla) and to provide guidelines for selecting suitable growing media for high-quality potted hydrangea production. The experiment was conducted under a containerized cultivation system using a Completely Randomized Design (CRD) with 12 treatments, 5 replications, and 4 plants per replication. Plants were grown in 8-inch plastic pots. The growing media consisted of loam soil as the base material, mixed with organic materials including dry compost, coarse charcoal, raw rice husk, coconut coir, and rice husk charcoal, as well as an inorganic material, coarse sand, in different proportions. Pots were arranged in a greenhouse covered with 70% shading net. Irrigation was applied using a drip system twice daily (morning and evening) for 15 minutes per session. A compound fertilizer (NPK 15-15-15) was applied at a rate of 5 g per pot in three applications: at transplanting, after the first data collection, and after the second data collection, over a total experimental period of 3 months. Growth parameters, including plant height, number of branches, and number of leaves, were recorded at 30, 60, and 90 days after transplanting. Data were analyzed using analysis of variance (ANOVA), and mean comparisons were performed using Duncan’s New Multiple Range Test (DMRT) at a 95% confidence level. The results showed that growing media significantly affected the growth of hydrangea (p < 0.05). The medium consisting of loam soil mixed with dry compost resulted in the highest plant height, number of branches, and number of leaves at all growth stages, followed by the medium containing loam soil mixed with coarse charcoal and dry compost. In contrast, the use of loam soil alone resulted in the lowest growth performance in several observation periods. These findings indicate that growing media containing organic matter combined with porous materials can effectively enhance the growth of potted hydrangea and can be used as a guideline for improving commercial production.